Device and Method for the Automatic Initiation of an Injection

ABSTRACT

A system and method to automatically initiate an injection procedure of a medicament into a patient. In the system, a delivery assembly includes an injector for infusing the medicament into the patient. Further, the system includes a monitor for detecting a parameter characteristic of the procedure, for instance, a pressure indicative of a partial vacuum between the injector and the injection site, a pressure exerted by the patient against the delivery assembly, a conductance, a capacitance, or an optical blood reading. Also, the system includes a timer for determining compliance of the parameter within a predetermined range during a first time interval. In response to the timer, an actuator initiates the injection procedure at the expiration of the first time interval. Further, the actuator may stop the injection procedure if the parameter is outside the predetermined range during a second time interval.

This application is a continuation of application Ser. No. 11/855,018,filed Sep. 13, 2007, which is currently pending. The contents ofapplication Ser. No. 11/855,018 are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention pertains generally to systems and methods forinjecting fluid medicaments into the body of a patient. Moreparticularly, the present invention pertains to injectors that can beused by a patient to self-administer a fluid medicament. The presentinvention is particularly, but not exclusively, useful as a system andmethod for ensuring proper conditions to prevent premature injectionsand to prevent the continuation of improper injections.

BACKGROUND OF THE INVENTION

As medical technology advances, increasing numbers of patients are ableto live with chronic conditions. Often, these patients are required toself-administer the necessary medications. In certain cases, the chronicconditions may require self-injection of one or more medications on aregular basis. Diabetes, for instance, is a common disease whichrequires sufferers to inject themselves with insulin one or more timeseach day.

Generally, self-administered injections are of the subcutaneous type.Subcutaneous injections are provided into the tissue just under the skinin order to provide a slower release of a medicinal substance into thebody and thus guard against over-reaction in other portions of the body.Typically subcutaneous injections are performed into the fascia and fattissue just under the skin.

When medical personnel perform a subcutaneous injection on patients,they usually pucker the flesh prior to applying the injection. As aresult, the skin and its associated underlying structures, including asubcutaneous adipose tissue, are essentially isolated. Further,puckering the flesh firms the surface fascia to facilitate insertion ofthe medicament. While it is not difficult for a medical person toperform a subcutaneous injection in this manner, a self-injection into apatient's arm, back of arm, or buttocks cannot be preformed with theflesh puckering technique.

To overcome this limitation, a number of injection devices have beendesigned specifically for self-injections. Such devices may utilize avacuum or other structure to properly prepare the patient's flesh for aninjection. While these devices make self-injections intodifficult-to-reach injection sites possible, it still can be difficultto correctly administer the required injection every time. Specifically,it can be difficult for a patient to determine when the injection siteis ready for an injection and to avoid premature injections. Also, itcan be difficult for a patient to ensure that injection conditions aremaintained throughout the injection so that the injection is effective.

In light of the above, it is an object of the present invention toprovide a system and method for performing injections that is convenientto use and that requires minimal manipulation before, during, and afteran injection. Another object of the present invention is to provide asystem and method for automatically initiating an injection procedurewhen predetermined injection conditions are met for a predeterminedperiod of time. Another object of the present invention is to provide asystem and method for automatically stopping the injection procedurewhen it is determined that injection conditions are no longer met. Stillanother object of the present invention is to provide a system andmethod for successfully performing self-injections with the use of onlyone hand. Another object of the present invention is to provide a systemand method for performing injections that is easy to use, is relativelysimple to manufacture, and is comparatively cost effective.

SUMMARY OF THE INVENTION

The present invention is directed to a system and method forautomatically initiating and stopping a procedure for injecting a fluidmedicament into a patient. As a result, the system assures thatdifficult injections, such as self-injections in difficult-to-reachareas of the body, are performed only when preferred injectionconditions are observed. For purposes of the present invention, thesystem includes a fluid delivery assembly that includes an injector thatinfuses a predetermined volume of the medicament into the patient.Structurally, the fluid delivery assembly includes a fluid chamber thatholds the fluid medicament in fluid communication with the injector. Inthe fluid delivery assembly, a plunger is positioned in the fluidchamber for advancement through the chamber to expel fluid through theinjector. Also, a drive mechanism is provided for advancing the plungerthrough the chamber.

In addition to the fluid delivery assembly, the system includes amonitor for detecting an operational parameter characteristic of theprocedure. Specifically, the operational parameter detected by themonitor may be a pressure that is indicative of a partial vacuumestablished between the injector and an injection site on the patient.It may also be a reaction pressure exerted by the patient against thefluid delivery assembly, a conductance, a capacitance, or an opticalblood reading.

Also, the system is equipped with a timer that is electronicallyconnected to the monitor to observe the operational parameter duringcontiguous first and second time periods. With this connection, thetimer may determine whether the operational parameter stays within apredetermined range throughout the first time interval and the secondtime interval. Further, the timer communicates with an actuator that isconnected to the fluid delivery assembly. For purposes of the presentinvention, the actuator is able to selectively initiate and stop theinjection procedure performed by the fluid delivery assembly.

In operation, the injector of the fluid delivery assembly is positionedat the injection site. Thereafter, the monitor detects the operationalparameter. As soon as the monitor has detected that the operationalparameter has successfully stayed within the predetermined range for thefirst time interval, the monitor alerts the actuator. In response, theactuator initiates the injection procedure by the fluid deliveryassembly. For the present invention, the length of time required for theinjection procedure coincides with the second time interval. Therefore,if the monitor determines that the operational parameter falls outsidethe predetermined range during the second time interval, the monitoralerts the actuator and the actuator stops the injection procedure. Inthis manner, the system ensures that effective injections areadministered and that non-effective injections are aborted.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of this invention, as well as the invention itself,both as to its structure and its operation, will be best understood fromthe accompanying drawings, taken in conjunction with the accompanyingdescription, in which similar reference characters refer to similarparts, and in which:

FIG. 1 is a perspective view of a patient performing a self-injection inaccordance with the present invention;

FIG. 2 is a schematic diagram of the operational components of the fluiddelivery assembly of the present invention;

FIG. 3A is a cross sectional view of the fluid delivery assembly of FIG.2 in accordance with the present invention;

FIG. 3B is a cross sectional view of the fluid delivery assembly of FIG.3A shown in engagement with the patient's skin and readied for aninjection; and

FIG. 4 is a schematic flow chart of the method of operation of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring initially to FIG. 1, a system for automatically initiating aninjection procedure to deliver a fluid medicament in accordance with thepresent invention is shown and is generally designated 10. For thepurposes of the present invention, the system 10 is used to deliver afluid medicament to a patient 12 by selectively injecting the fluidmedicament either into a muscle (intra-muscular), subcutaneous, or intothe skin (intra-dermal). For all modes of operation, the system 10essentially includes a housing 14 that contains a fluid deliveryassembly 16 and components for monitoring and automatically acting onoperational parameters as discussed below. To stabilize and hold thefluid delivery assembly 16 against the skin 18 of the patient 12 duringan injection, the system 10 may include a suction pump 20 which may beintegrated into housing 14 and connected in fluid communication with thefluid delivery assembly 16 via a vacuum line 22. More specifically, thegeneration of a partial vacuum between the fluid delivery assembly 16and the skin 18 of the patient 12 accomplishes at least three functions.First, the partial vacuum forms the skin 18 with a desired tension forthe injection. It should be noted that the desired tension for anintra-muscular injection is different than the tension for anintra-dermal injection. Second, as stated above, the partial vacuumhelps stabilize and hold the fluid delivery assembly 16 against thepatient 12. And third, the partial vacuum generates a fluid seal betweenthe fluid delivery assembly 16 and the patient 12 that allows for theeffective delivery or injection of a fluid medicament.

Referring now to FIG. 2, the system 10 is illustrated as includinginternal components in the fluid delivery assembly 16. Specifically, thesystem includes a monitor 24 for detecting an operational parametercharacteristic of the injection procedure. For instance, the monitor 24may be a pressure sensor that measures a partial vacuum establishedbetween the fluid delivery assembly 16 and the skin 18 of the patient 12at the injection site 26. Similarly, the monitor 24 may be a pressuresensor that measures the reactive pressure exerted by the patient 12against the fluid delivery assembly 16 when the fluid delivery assembly16 is brought into contact with the skin 18 before an injection.Alternatively, the monitor 24 may include an electric lead for measuringconductance, or a receiver for measuring capacitance. In otherembodiments, the monitor 24 may comprise an optical device for bloodreading. In any case, the monitor 24 is provided to detect the desiredoperational parameter, whether it be pressure, conductance, capacitance,or blood composition.

As shown in FIG. 2, the monitor 24 is electronically connected to atimer 28. With this connection, the timer 28 is able to determinewhether the operational parameter detected by the monitor 24 stayswithin a predetermined range during a first time interval “Δt₁” andduring a second time interval “Δt₂”. In FIG. 2, the monitor 24 and timer28 are also connected to a controller 29. For purposes of the presentinvention, the controller 29 provides the ability to select theoperational parameter, the predetermined range and the time intervals.Further, the controller 29 is connected to an actuator 30 which isconnected to the fluid delivery assembly 16. With this design, theactuator 30 may initiate an injection procedure when activated by thecontroller 29.

It is to be appreciated that the functionality of the monitor 24, timer28 and controller 29 should be considered in combination with each otheras a unified control element. Specifically, it is important that such acontrol element detect an operational parameter and ascertain it to havea predetermined value, at specified times, for required time intervals.This can be accomplished in any of several different ways. For one, themonitor 24, timer 28 and controller 29 can interact with each other as acontrol element in a manner as described above. Also, in alternateembodiments for the present invention, the combined functions of thecontrol element can be accomplished by devices such as: 1) softwarebased microcontroller; 2) discrete electronic components such astransistors, resistors and capacitors; 3) discrete logic integratedcircuits such as a comparator and timer; or 4) integrated logic circuitsuch as a programmable gate array.

Referring now to FIG. 3A, the construction of the fluid deliveryassembly 16 is shown. In FIG. 3A, the fluid delivery assembly 16includes an injector 32 for infusing a predetermined volume ofmedicament 34 into the patient 12. Structurally, the fluid deliveryassembly 16 forms a fluid chamber 36 that holds a predetermined volume37 of the fluid medicament 34 in fluid communication with the injector32. As shown, the chamber 36 defines an axis 38. Further, a plunger 40is positioned in the fluid chamber 36 for advancement along the chamberaxis 38 through the chamber 36 to expel fluid medicament 34 through theinjector 32. Also, a drive mechanism 42, such as a screw or spring, isprovided for controlling movement of the plunger 40 in the chamber 36.As shown, a lead 44 connects the drive mechanism 42 to the actuator 30(shown in FIG. 2).

In the embodiment shown in FIG. 3A, the injector 32 is illustrated as aneedleless type. Further, the fluid delivery assembly 16 forms adepression 46 around the external tip 48 of the injector 32. As shown,the vacuum line 22 is in communication with the depression 46 to providea partial vacuum in the depression 46. Further, the monitor 24 isprovided at the depression 46 to measure the pressure therein (or otheroperational parameter as desired). Referring now to FIG. 3B, the effectof a partial vacuum in the depression 46 is illustrated. In FIG. 3B, thefluid delivery assembly 16 has been positioned at the injection site 26and the vacuum line 22 has created a partial vacuum to draw thepatient's skin 18 into the depression 46. As shown, the monitor 24 isable monitor the pressure in the depression 46. It is noted that FIG. 3Bshows an alternate injector 32 which utilizes a needle 49.

Referring now to FIG. 4, the operation of the system 10 may beunderstood. As shown in FIG. 4, operation commences when an injector isprepared and the injector 32 is positioned at the injection site 26(action block 50). For purposes of the present invention, this step mayinclude programming the controller 29 with the predetermined volume 37to be injected, the predetermined range for the operational parameterand the length of the first and second time intervals. Alternatively,each of these variables may be preset and unadjusted. For exemplarypurposes, the predetermined volume may be 0.3 cubic centimeters, thepredetermined range for partial vacuum pressure may be approximately 1to 5 psia, the first time interval may be 2 seconds, and the second timeinterval is determined by the time necessary to infuse the required doseof fluid medicament.

After the injector 32 is positioned at the injection site 26, theoperational parameter is detected by the monitor 24 (action block 52).As shown in inquiry block 54, the controller 29 determines whether theoperational parameter has remained within the predetermined range forthe first time interval. If it has not, the method returns to actionblock 52, or even action block 50 if the injector 32 needs to berepositioned at the injection site 26. If the operational parameter hasremained within the predetermined range for the first time interval, thecontroller 29 prompts the actuator 30 to initiate the injectionprocedure (action block 56). During the injection, which lasts as longas the second time interval, the monitor 24 continues to detect theoperational parameter as commenced in action block 52. As a result, ininquiry block 58, it is determined whether the operational parameter hasremained within the predetermined range during the second time interval.As long as the operational parameter has been kept within thepredetermined range, the injection may be completed at action block 60,and the operation may be concluded. If the operational parameter fallsoutside the predetermined range during the second time interval, theinjection is stopped at action block 62. Thereafter, the injectionprocedure may be restarted at action block 50.

As can be seen from FIG. 4, the system 10 operates to prevent anypremature injections, i.e., injections before an appropriate interfaceof the injector 32 with the skin or flesh has been established. As aresult, patients can be confident that injections at difficult-to-reachareas will be accurate and properly administered. Further, the system 10ensures continued engagement for infusion, thereby preventing injectioninterruptus.

While the particular Device and Method for the Automatic Initiation ofan Injection as herein shown and disclosed in detail is fully capable ofobtaining the objects and providing the advantages herein before stated,it is to be understood that it is merely illustrative of the presentlypreferred embodiments of the invention and that no limitations areintended to the details of construction or design herein shown otherthan as described in the appended claims.

1. A system for automatically initiating an injection procedure forinjection of a fluid medicament into a patient which comprises: a fluiddelivery assembly having an injector for infusing a predetermined volumeof the medicament into the patient; a control element for setting apredetermined range of values of an operational parameter characteristicof the procedure and a first time interval “Δt₁”; a monitorelectronically connected to the control element for detecting theoperational parameter characteristic of the procedure; a timerelectronically connected to the monitor for observing the operationalparameter characteristic of the procedure and determining whether theoperational parameter characteristic stays within a predetermined range;and an actuator connected to the fluid delivery assembly, and responsiveto the timer, for initiating the injection procedure by the fluiddelivery assembly at the expiration of the first time interval “Δt₁”. 2.A system as recited in claim 1 wherein the fluid delivery assembly isoperable to infuse the fluid medicament during a second time interval“Δt2”, and wherein the actuator stops the injection procedure during thesecond time interval “Δt2” when it is determined the operationalparameter is outside the predetermined range.
 3. A system as recited inclaim 2 wherein the first time interval “Δt1” is contiguous with thesecond time interval “Δt2”.
 4. A system as recited in claim 2 whereinthe control element is reset after expiration of the second timeinterval “Δt2”.
 5. A system as recited in claim 1 wherein the injectoris a needleless injector, and the operational parameter is a pressurevalue indicative of a partial vacuum established between the injectorand an injection site on the patient.
 6. A system as recited in claim 1wherein the injector is a needle, and the operational parameter is areaction pressure exerted by the patient against the fluid deliveryassembly.
 7. A system as recited in claim 1 wherein the operationalparameter is selected from a group consisting of a conductance, acapacitance and an optical blood reading.
 8. A system as recited inclaim 1 wherein the fluid delivery assembly comprises: a fluid chamberfor holding the fluid medicament, wherein the fluid chamber is in fluidcommunication with the injector; and a plunger positioned in the fluidchamber for advancement therethrough to expel fluid therefrom throughthe injector.
 9. A system as recited in claim 8 further comprising adrive mechanism for advancing the plunger.
 10. A system forautomatically initiating and terminating an injection procedure forinjection of a fluid medicament into a patient which comprises: a fluiddelivery assembly having an injector for infusing a predetermined volumeof the medicament into the patient; a control element for setting afirst predetermined range of values of a first operational parametercharacteristic and a second predetermined range of values of a secondoperational parameter characteristic of the procedure and a first timeinterval “Δt₁” and a second time interval “Δt₂”; a monitorelectronically connected to the control element for detecting the firstoperational parameter characteristic and the second operationalparameter characteristic of the procedure; a timer electronicallyconnected to the monitor for observing the first operational parametercharacteristic during the first time interval “Δt₁” and the secondoperational parameter characteristic during the second time interval“Δt₂” to determine whether the first operational parametercharacteristic stays within the first predetermined range during thefirst time interval “Δt₁” and whether the second operational parametercharacteristic stays within the second predetermined range during thesecond time interval “Δt₂”; and an actuator connected to the fluiddelivery assembly, and responsive to the timer, for initiating theinjection procedure by the fluid delivery assembly at the expiration ofthe first time interval “Δt₁” and for terminating the injectionprocedure at the expiration of the second time interval “Δt₂”.
 11. Asystem as recited in claim 10 wherein the first time interval “Δt₁” iscontiguous with the second time interval “Δt₂”.
 12. A system as recitedin claim 10 wherein the control element is reset after expiration of thesecond time interval “Δt₂”.
 13. A system as recited in claim 10 whereinthe injector is a needleless injector, and the first operationalparameter is a pressure value indicative of a partial vacuum establishedbetween the injector and an injection site on the patient.
 14. A systemas recited in claim 10 wherein the injector is a needle, and the firstoperational parameter is a reaction pressure exerted by the patientagainst the fluid delivery assembly.
 15. A system as recited in claim 10wherein the first operational parameter is selected from a groupconsisting of a conductance, a capacitance and an optical blood reading.16. A system as recited in claim 10 wherein the second operationalparameter is the fluid medicament in the fluid delivery assembly.
 17. Amethod for automatically conducting an injection procedure for injectionof a fluid medicament into a patient which comprises the steps of:providing a system including a fluid delivery assembly having aninjector, a monitor, a timer electronically connected to the monitor,and an actuator responsive to the timer and connected to the fluiddelivery assembly; setting the monitor with a first predetermined rangeof values of a first operational parameter characteristic of theprocedure and a second predetermined range of values of a secondoperational parameter characteristic of the procedure; setting the timerwith a first time interval “Δt₁” and a second time interval “Δt₂”;positioning the injector at an injection site on the patient; detectingwith the monitor the first operational parameter characteristic of theprocedure, wherein the detected first operational parameter isindicative of an interaction between the system and the patientbeginning before infusion of the medicament into the patient;determining continued compliance of the first operational parameter at avalue in a first predetermined range, during the first time interval“Δt₁”; initiating with the actuator, in response to the determiningstep, the injection procedure by the fluid delivery assembly at theexpiration of the first time interval “Δt₁” and the immediatecommencement of the second time interval “Δt₂”; and infusing with theinjector a predetermined volume of the medicament into the patientduring the injection procedure during the second time interval Δt₂,wherein the injection procedure is stopped when the second time intervalΔt₂ expires.
 18. A method as recited in claim 17 wherein the first timeinterval “Δt₁” is contiguous with the second time interval “Δt₂”.
 19. Amethod as recited in claim 17 wherein the injector is a needlelessinjector, and wherein the operational parameter is selected from a groupconsisting of a conductance, a capacitance, an optical blood reading, apressure value indicative of a partial vacuum established between theinjector and an injection site on the patient, and a reaction pressureexerted by the patient against the fluid delivery assembly.
 20. A methodas recited in claim 17 further comprising the step of resetting thefirst operational parameter characteristic, the second operationalparameter characteristic, the first time interval “Δt₁”, and the secondtime interval “Δt₂” after the completion of the infusing step.